php 生成唯一id /唯一标识符/唯一订单号

/**

 * php 生成唯一id

 * http://blog.csdn.net/hzqghost/article/details/18914681
 */

function guid($factor='',$prefix='',$suffix=''){

    list($usec, $sec) = explode(" ", microtime());  

    $guid = $prefix. $factor. $_SERVER['HTTP_USER_AGENT'] . $_SERVER['REMOTE_ADDR']  

           . $sec . $usec   

           . mt_rand(0,1000000).time(). mt_rand(0,1000000).$suffix;  

    $guid = substr(sha1($guid),8,32); 

    $guid = base_convert($guid,16,36);  

    return $prefix.$guid.$suffix;

}

//生成唯一标识符   //sha1()函数， "安全散列算法（SHA1）"   

function create_unique(){

    $data = $_SERVER['HTTP_USER_AGENT'].$_SERVER['REMOTE_ADDR'].time().rand();

    return sha1($data);//return md5(time().$data);   //return $data;   

}

//生成24位唯一订单号

function create_orderid(){

    return date('Ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);

}